Yeah Guy is extremely overrated. Surely without a doubt if you fight him 1 on 1, you will be in trouble, because of his gates. But the effect of the gates wears off rather fast, and then he will lose, because the after effects simply "defeats" him. So all you gotta do, is to keep calm and wait. Easier said than done, but such a jutsu is not really suited for many types of situations.
His advantage is, that most people would see him as a rather stupid and probably easy to outsmart opponent, however, judging a book by its cover will be fatal. Guy is exactly the opposite! And he's good at getting on people's nerves, another very fine attribute in shinobi battles.